Lav errorbars for silica.
## [1] NA -36.6459627 -37.1929825 -59.8152425 NA NA
## [7] 23.7603306 0.1164144 -15.4061625 NA NA -32.8358209
## [13] -71.8446602 -57.1428571 NA NA -6.3829787 -15.0943396
## [19] -26.7206478 NA
## [1] -35.015604 -59.162963 -33.413493 -53.171969 -7.589930 -5.764298 -12.671641
## [8] -15.575756